Problem: Express your answer as a mixed number simplified to lowest terms. $6\dfrac{4}{7}-1\dfrac{3}{4} = {?}$
Explanation: Find a common denominator for the fractions: $= {6\dfrac{16}{28}}-{1\dfrac{21}{28}}$ Convert ${6\dfrac{16}{28}}$ to ${5 + \dfrac{28}{28} + \dfrac{16}{28}}$ So the problem becomes: ${5\dfrac{44}{28}}-{1\dfrac{21}{28}}$ Separate the whole numbers from the fractional parts: $= {5} + {\dfrac{44}{28}} - {1} - {\dfrac{21}{28}}$ Bring the whole numbers together and the fractions together: $= {5} - {1} + {\dfrac{44}{28}} - {\dfrac{21}{28}}$ Subtract the whole numbers: $=4 + {\dfrac{44}{28}} - {\dfrac{21}{28}}$ Subtract the fractions: $= 4+\dfrac{23}{28}$ Combine the whole and fractional parts into a mixed number: $= 4\dfrac{23}{28}$